This invention relates to an apparatus and method for assembling components of elongated jewelry articles such as chains.
In the assembly of such chains, the chain is initially cut to length and end caps or D-rings are secured to the ends by welding or soldering. These steps are typically accomplished by hand although it is known to automatically weld D-rings to the ends of such chains. See for example U.S. Pat. No. 4,298,154. Subsequently, a spring ring is secured to one of the ends or rings whereby the chain may be opened and closed. Typically, a quality tag is secured to a D-ring. When the quality tag is secured to such a ring, the ring is typically a split ring which is opened and then closed. Further, the spring ring has a split bail which is opened and threaded through the end cap, or D-ring or quality tag and then closed. These steps are normally performed by hand.
The present invention is directed to an apparatus wherein a chain is taken from a spool, measured and cut. Clamps engage and transport the ends of the chain to an assembly station where fasteners such as end caps or D-rings are soldered onto the ends of the chain. The bail of a spring ring is opened, passed through the one D-ring or end cap and closed. A quality tag may or may not be added as a step in the assembly. Lastly, the spring ring is opened and secured to the other D-ring or end cap and thus the chain is closed and placed on a rod or the like. These steps are all programmed and performed automatically.
The assembly station is defined generally as including the soldering platform, the various fastener feeders (as will be described), a ring twisting station and a robot arm. The apparatus can assemble chains employing any type of `fastener` including but not limited to rings, O-rings, quality tags, spring rings, caps, fish-hooks, lobster claws and sister hooks which are now available.
The invention broadly embodies a robotic system and method of using that system. In one aspect of the invention, three robotic hands or grippers are used in combination to assemble a product.
In its preferred embodiment, the invention is used for measuring chain lengths, securing fasteners to the ends of the chain and securing the fasteners to one another. In one aspect of the preferred embodiment, a chain length may be measured and cut at a predetermined length, which length exceeds the distance that a gripper(s) engaging the chain can physically travel. That is, a chain can be measured and cut at a length which exceeds the structural dimensions of the system.
In another aspect of the invention, feeders for fasteners are provided which select a fastener out of a random array of fasteners, move the fastener to a predetermined position (known orientation) whereby the fastener may be acquired by a robotic gripper for assembly to a chain or other fastener.
In a further aspect of the invention, a structure and method are provided for physically securing the fasteners to the chain and to one another.
In a still further aspect of the invention, the three robotic grippers are used to secure the ends of the chain one to the other thereby forming a closed loop.
In a particularly preferred embodiment, the invention comprises an apparatus for securing fasteners to the ends of a chain wherein a shearing station is disposed at one end of an elongated housing and an assembly station is disposed at the other end of the housing. At least two clamps are provided, a first clamp to engage one end of the chain and a second clamp to engage the other end of the chain. The clamps are adapted to move the chain between the shearing station and the assembly station. Further, control means are provided to effect the relative movement of the clamps, securing of fasteners to the chains and the securing of the fasteners one to the other.
The method of the invention comprises clamping one end of a chain, forming a second end of the chain, clamping the second end of the chain and moving one of said ends to an assembly station to secure a fastener to said end, and the two finished ends of the chain are attached to form a closed loop (chain).